Test access mechanism for multiple identical cores

A new test access mechanism (TAM) for multiple identical embedded cores is proposed. It exploits the identical nature of the cores and modular pipelined circuitry to provide scalable and flexible capabilities to make tradeoffs between test time and diagnosis over the manufacturing maturity cycle from low-yield initial production to high-yield, high-volume production. The test throughput gains of various configurations of this TAM are analyzed. Forward and reverse protocol translations for core patterns applied with this TAM are described.